China may have passed a milestone in the quest to put its first nuclear-armed submarines on patrol — the final pillar of Beijing’s nuclear deterrent that could reset military thinking in Washington and redraw Asian geopolitics.

Defence sources told The Times that China has secretly recruited six crews to man its Jin-class Type 094 submarines, which have been under development for some years and may be undergoing another round of upgrades.

Although China was previously known to have built two of the submarines, Western defence analysts have been unable to pinpoint how many it now has, but it is believed that